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1. 9kg.........153lei
5kg............X lei

12tractoare...........15ore
20tractoare..........y ore


Răspuns :


Rezolvi prin raport, adica

1) [tex] \frac{9}{5} = \frac{153}{x} inmultesti in cruce 9x = 765, de unde x = 85 [/tex]



2) [tex] \frac{12}{20} = \frac{15}{y} inmultesti in cruce 12y = 300, de unde y=25[/tex]



9/5=153/x
9x=153x5
x=765:9
x=85

12/20=15/y
12y=15x20
y=300:12
y=25